Replaceable resilient pad assembly for abrasive finishing articles

ABSTRACT

A throwaway resilient pad assembly formed of a body of resilient material having first and second side faces. The side faces are such that a plurality of abrasive finishing members can be adhered sucessively thereto. A disc-like member having a central opening is formed in the body of resilient material. The pad assembly is removably coupled to a drive member at the central opening of the disc-like member. The drive member may then be affixed to a power tool for imparting movement to the resilient pad assembly and finishing members. The faces of the resilient member may be constructed of a cloth material to which the finishing member is adhered. A drive shaft can be attached to the disc-like member at the central opening.

e States Ptent 1 1 lllaigh et a1.

REPLACEABLE RESILIENT PAD ASSEMBLY FOR ABRASIVE FINISHING ARTICLESInventors: Jack M. Halgh, l4 Overlook PL,

Rye, NY. 10580; Joseph 11. MacKay, Jr., 20 Vanech Dr., Stamford, Conn.06904 Filed: Jan. 5, 1973 Appl. No.: 321,431

References Cited UNITED STATES PATENTS Buzzell 51/378 StratfordStratford.....

Patt Cosmos...

[ 1 Oct. 29, 1974 2,644,280 7/1953 ONeil 15/406 Primary ExaminerAlLawrence Smith Assistant Examiner--Nicholas P. Godici Attorney, Agent,or Firm-Nilsson, Robbins, Bissell, Dalgarn & Berliner [5 7 ABSTRACT Athrowaway resilient pad assembly formed of a body of resilient materialhaving first and second side faces. The side faces are such that aplurality of abrasive finishing members can be adhered sucessivelythereto. A disc-like member having a central opening is formed in thebody of resilient material. The pad assembly is removably coupled to adrive member at the central opening of the disc-like member. The drivemember may then be affixed to a power tool for imparting movement to theresilient pad assembly and finishing members. The faces of the resilientmember may be constructed of a cloth material to which the finishingmember is adhered. A drive shaft can be attached to the disc-like memberat the central opening.

7 Claims, 3 Drawing Figures IIIII REPLACEABLE RESILIENT PAD ASSELY FORABRASIVE FINISHING TICLES BACKGROUND OF THE INVENTION 1. Field of ArtThe field of art to which the invention pertains includes the field ofabrasive finishing articles, particularly with respect to a throwawayresilient pad assembly for supporting such articles.

2. Description of the Prior Art Known resilient pad assemblies, such asthose used to support adhesively secured abrasive finishing articlesdriven by conventional power tools, are constructed of a sponge bodyhaving a cloth face on one side thereof and a support backing on theopposite side. The support backing includes a drive member which isriveted or bolted to the support layer and, in turn, may be threaded orotherwise secured to the drive shaft of a power tool. Abrasive finishingarticles are attached to the cloth face with adhesives. When such anarticle becomes worn, another is adhered or glued to the cloth face. Asthe worn finishing articles are repeatedly removed from the pad, thecloth face tends to separate from the sponge, taking portions of thesponge body therewith creating holes in the face of the pad. Repeatedreplacement of the finishing articles causes a build-up of glue on thecloth face resulting in further irregularities. As the pad with adheredfinishing article is used, the edges of the pad are constantly broughtinto contact with the workpiece. Such contact, or bumping, createsfurther wear on thesponge body. As a result of the repeated glueing ofthe finishing articles on the cloth face, as well as the bumping of theedge of the sponge material on the workpiece during use thereof, it hasbeen found that such prior art resilient pads wear out rather rapidly.In addition, the natural breakdown of the sponge material from prolongeduse, as well as from damage as above described, requires the resilientpad be discarded after a relatively short life. Since prior art padsinclude a sponge body and cloth face formed integrally with the entiresupport backing assembly, the entire structure must be discarded, eventhough the supporting and-attaching members retain their integnty.

In order to overcome the attendant disadvantages of prior art resilientpad assemblies, the present invention provides a resilient pad which canbe replaced while retaining the structural portion of the assembly. Thepad can be reversed when one face thereof is no longer usable, and, dueto the support of the sponge portion of the pad, the breakdown of thesponge body does not occur as rapidly as in conventional pad assemblies,yet the same "feel experienced by users of the pads is retained.Moreover, an oversized pad can be used on a smaller diameter supportstructure to give a softer edge .which may be desirable when the pad isused with an abrasive finishing article for certain contoured material.This softness is obtained in conventional prior art pads only by using athicker, softer sponge which increases wear of the sponge, resulting inan even shorter life. Should any part of the support mechanism bedamaged, it can be replaced rather than replacing the entire supportassembly.

SUMMARY OF THE INVENTION A throwaway pad assembly formed of a body ofresil- 2 ient material having first and second side faces. A disclikemember having a central opening is formed in the body of resilientmaterial. An abrasive finishing article may be secured to one of thefaces during use. The central opening receives a drive member forimparting movement to the assembly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective viewof a pad assembly made in accordance with the invention;

FIG. 2 is a view, partly in section, of the pad assembly of FIG. Imounted on a support structure; and

FIG. 3 is a fragmentary view, partly in section, of an alternativearrangement of a pad assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, thereis shown a resilient pad 12 made in accordance with the principles ofthe invention. The pad 12 is normally secured to a pad holder, and theentire assembly then coupled to a drive member which causes the pad torotate when affixed to a power tool. While the pad has many uses, it isshown illustrated as having an abrasive finishing article such as apaper disc of sandpaper mounted thereon.

The resilient pad 12 is shown in FIG. I in an exploded perspective viewprior to assembly in a sandwich configuration. The pad comprises a firstouter face member 14 having a central opening 16 therein and a secondouter face member 18 having a central opening 22 therein. The first andsecond outer face members are normally identical thin layers of materialsuch as duck cloth but may be formed -of plastic, rubber, or the like.Positioned between the face members 14 and 18 are a first sponge layer24 adjacent the member 14 and having an opening 26 therein, and a secondsponge layer 28 adjacent the member 18 and having an opening 32 therein.The face members 14 and I8, as well as the sponge layers 24 and 28, haveequal diameters, although the face members 14 and I8 may be madeslightly larger. In addition, each of the openings 16, 22, 26 and 32 arenormally concentric.

Positioned between the first sponge layer 24 and the second sponge layer28 is a central semi-rigid, but flexible, disc 34 having an outerdiameter slightly smaller than that of the face member and spongelayers. The disc may be formed of plastic, metal, or the like so long asthe desired flexibility and semi-rigidity is retained. A non-circularopening such as the hexagonally shaped opening 36 is formed in thecenter of the disc 34. Cylindrical flanges 38 extend in both directionsfrom the center of the disc 34 along an axis perpendicular to the disc.The hexagonal opening 36 forms the inner surface of the flanges and theouter edges 42 of the flanges 38 have a diameter slightly smaller thanthe openings in the face members and the sponge layer.

In assembly, as shown in FIG. 2, the plastic disc is centrallypositioned between the first sponge layer 24 and the second sponge layer28, and normally secured thereto by any conventional adhesive compatiblewith the layers 24 and 28. The openings 26 and 32 of the sponge layers,respectively, surround the flanges 38 and rest on the outer edge 42thereof. Then the first face member 14 and the second face member 18 aresecured to the outer surfaces of the first sponge layer 24 and thesecond sponge layer 28, respectively, also utilizing any desiredadhesive. Normally, the face members can be laminated to the spongelayers in sheet form and then can be die-cut as one unit.

The resilient pad 12 may be used to support an abrasive finishingarticle, such as sandpaper which is illustrated in FIG. 1 as a paperdisc 44. It should be noted that the resilient pad 12 is arranged in amanner such that a paper disc can be glued to either face member 14 or18. Thus, should wear or glue build-up occur on either outer surface ofthe face members, the resilient pad can be reversed and a paper discthen glued on the other face member.

When the resilient pad 12 is assembled, it is then mounted on a padholder. As illustrated in FlG. 2, the pad holder is formed of a bolt 60having a hex head 62 which is inserted into the hexagonal opening 36 ofthe central plastic disc 34. It should be noted that the hex head 62 andopening 36 could be of shape other than hexagonal. Extending from oneside of the hex head is a shaft 64 of the bolt 60 which contains aninternal bore 66 extending from the hex head to an interior portion ofthe shaft. The outer surfaces of the shaft 64 and the bore 66 arethreaded. A washer 68 is positioned over the shaft 64 adjacent the hexhead. The washer 68 has a thickness approximately equal to the thicknessof the first sponge layer 24 and is positioned in the opening 26 The padholder is further formed of a first plastic disc 72 positioned with oneside thereof adjacent the first face member 14 and a disc opening 74enables the disc 72 to fit over the shaft 64. The diameter of the disc72 is slightly smaller than that of the face member 14. In addition, asecond plastic disc 76 having an opening 78 therein is fitted over theshaft 64 and positioned adjacent the disc 72. The disc 76 has a diametersmaller than that of the disc 72. Finally, an enlarged locking nut 82having a threaded interior opening 84 and a pair of openings 86 and 88is positioned over the shaft 64 by threading the opening 84 onto theshaft 64. The openings 86 and 88 enable a tool, such as a spannerwrench, to grasp the nut and thereby tighten it.

At the other end of the assembly, a threaded bolt 92 is threaded intothe internal bore 66 of the bolt 60. The bolt 92 has an enlarged flangehead 94 whose outer edge rests against one side of the flange 38 of thedisc 34, and prevents separation of the pad 12 from the pad holder.While the assembly is shown with a pair of discs 72 and 76, it should benoted that the assembly could be used with only one of these discs. Thedimension of the disc adjacent the pad varies the amount of flexibilityat the outer edge of the resilient pad. It should be noted that when theshaft 64 is secured to a drive member such as a drill, that all driveforces are taken by the central plastic disc 34.

The central plastic disc can be glued between the sponge layers and theface members in turn glued to the outer surface of the sponge layers byany conventional type adhesive which is compatable with the materiallayers. Typically, the central plastic disc 34 is made of moldedthermoplastic material such as Nylon or Delrin; however, other materialssuch as metal or thermosetting plastic could also be used, so long asthe central disc can be secured to an attaching device. In addition, thecentral disc is flexible and extends almost to the edge of the spongelayers 24 and 28 in order to keep the edges of the sponge layers frombreaking down. The sponge layers 24 and 28 are normally made of neoprenesponge of approximately /8 inch thickness each.

This thickness provides less opportunity to allow a breakdown of thesponge. It has been found that as the sponge thickness increases, theopportunity for sponge breakdown is also increased. While previously Ainch to 5/16 inch thickness sponges have been used, because it has beenfound that operators would obtain a desired feel" with such thickness,the Vs inch thickness sponge layers 24 and 28 do not break down asreadily, yet when assembled with the plastic disc, the desired feel" isretained. Typically, the face members 14 and 18 are made of duck cloth,although the assembly could be made without the duck cloth faces byproviding a special skin molded on the outer face of the sponge layersto give additional strength and durability to the sponge. However, theduck cloth material has been found to be a desirable configuration forsecuring the paper disc to the pad assembly.

In FIG. 3, there is illustrated an alternative arrangement forassembling as well as driving a throw-away pad assembly. The embodimentof FIG. 3 utilizes a disc-like member 102 which typically can be made ofa thermoplastic material and contains a central opening 104 whichextends from a first side 106 to a second side 108. The sides 106 and108 may taper from the central opening 104 to the edge 112 of the member102. The disc-like member 102 may be rigid in the area of the centralopening 104 and, depending on the degree and type of taper, either rigidor flexible in the area of the edge 112. A foam body 114 is molded inplace around the member 102 and is spaced from the central opening 104.The foam body 114 also extends beyond the edge 112 of the rigid member.The resultant combined configuration of the tapered disc-like member 102and foam body 114 forms a uniform cross-section except for the areaadjoining the opening 104.

Secured to the outer surfaces 116 and 118 of the foam member 114 are apair of face members 122 and 124, respectively. These face members 122and 124 may be formed of cloth, rubber, plastic or other suitablematerial or may be molded as a skin surface of the foam body 114. Theface members 122, 124 have openings 126, 128, respectively, which enablethe members to be secured to the sponge layers yet enable a drive memberto be secured to the threaded opening 104 of the rigid member 102. Theface members 122 and 124 may be secured to the foam member surfaces 116and 118 by means of an adhesive such as that utilized in the arrangementof FIGS. 1 and 2. The arrangement of FIG. 3, which utilizes a more rigiddisc-like member 102, eliminates the need for a rigid backing membersuch as the discs 72 and 76 of FIG. 2.

When a tapered disc-like member 102 of FIG. 3 is used, it is normallynecessary to mold the foam directly to the member 102. Should a flatdisc-like member of uniform crosssection be used in place of the tapereddisc of HO. 3, a foam layer could be placed on opposite sides of thedisc-like member, as in the arrangement of FIG. 1, where the spongelayers 24 and 28 are placed on opposite sides of the central disc member34. How ever, the tapered disc-like member 102 enables the edge pressureof the pad assembly to vary with the amount of taper.

We claim:

1. A reversible symetrically formed replaceable pad assembly comprising:

a body of resilient material having a central opening therein, said bodyhaving a disc-like member formed therein, said disc-like member radiallyextending into said body and having a central opening formed therein,said disc-like member central opening being smaller than said bodycentral opening, an axially central portion of said disc-like 5 memberthereby extending into said body opening and having a thickness thereatgreater than remaining portions of said disc-like member but less thanthe thickness of said body thereat, said openings being co-axial witheach other, said body having a first side face and a second side face;

means formed on said faces for securing an abrasive finishing article toeither one of said faces;

drive means; and

securing means positioned in said openings for securing said assembly tosaid drive means for imparting movement to said assembly, said securingmeans having an outer flange smaller than said body opening for abuttingsaid axial central portion of said disc-like member and being operablewhen ins int rs isiconc in f m,..,ith .Qf Said faces and securedtherein.

2. A reversible replaceable pad assembly in accordance with claim 1wherein said first means comprises a cloth face material to which saidabrasive finishing article is secured.

3. A reversible replaceable pad assembly in accordance with claim 1wherein said disc-like member extends near to the edge of said resilientmember for preventing structural failure of said resilient member.

4. A reversible replaceable pad assembly in accordance with claim 3wherein said layers of resilient material are made of a sponge-likematerial.

5. A reversible replaceable pad assembly in accordance with claim 1wherein said body of resilient material is formed of plastic foam whichis molded to said disc-like member on both sides thereof.

6. A reversible replaceable pad assembly in accordance with claim 5wherein said disc-like member tapers from a maximum cross-sectionalthickness adjacent said central opening to a minimum thickness adjacentthe edge of said plastic foam.

7. A reversible replaceable pad assembly in accordance with claim 6wherein said central opening is threaded.

1. A reversible symetrically formed replaceable pad assembly comprising:a body of resilient material having a central opening therein, said bodyhaving a disc-like member formed therein, said disclike member radiallyextending into said body and having a central opening formed therein,said disc-like member central opening being smaller than said bodycentral opening, an axially central portion of said disc-like memberthereby extending into said body opening and having a thickness thereatgreater than remaining portions of said disc-like member but less thanthe thickness of said body thereat, said openings being co-axial witheach other, said body having a first side face and a second side face;means formed on said faces for securing an abrasive finishing article toeither one of said faces; drive means; and securing means positioned insaid openings for securing said assembly to said drive means forimparting movement to said assembly, said securing means having an outerflange smaller than said body opening for abutting said axial centralportion of said disc-like member and being Operable when inserted intosaid opening from either of said said faces and secured therein.
 2. Areversible replaceable pad assembly in accordance with claim 1 whereinsaid first means comprises a cloth face material to which said abrasivefinishing article is secured.
 3. A reversible replaceable pad assemblyin accordance with claim 1 wherein said disc-like member extends near tothe edge of said resilient member for preventing structural failure ofsaid resilient member.
 4. A reversible replaceable pad assembly inaccordance with claim 3 wherein said layers of resilient material aremade of a sponge-like material.
 5. A reversible replaceable pad assemblyin accordance with claim 1 wherein said body of resilient material isformed of plastic foam which is molded to said disc-like member on bothsides thereof.
 6. A reversible replaceable pad assembly in accordancewith claim 5 wherein said disc-like member tapers from a maximumcross-sectional thickness adjacent said central opening to a minimumthickness adjacent the edge of said plastic foam.
 7. A reversiblereplaceable pad assembly in accordance with claim 6 wherein said centralopening is threaded.